scholarly journals Osteoblast Differentiation and Bone Matrix Formation In Vivo and In Vitro

2017 ◽  
Vol 23 (3) ◽  
pp. 268-280 ◽  
Author(s):  
Harry C. Blair ◽  
Quitterie C. Larrouture ◽  
Yanan Li ◽  
Hang Lin ◽  
Donna Beer-Stoltz ◽  
...  
Keyword(s):  
Osteoblast Differentiation ◽  
Bone Matrix

scholarly journals Regulation of Proliferation, Differentiation and Functions of Osteoblasts by Runx2

2019 ◽  
Vol 20 (7) ◽  
pp. 1694 ◽  
Author(s):  
Toshihisa Komori
Keyword(s):  
Osteoblast Differentiation ◽  
Matrix Protein ◽  
Gene Dosage ◽  
Bone Matrix ◽  
Mesenchymal Cells ◽  
Heterozygous Mutation ◽  
Chondrocyte Maturation ◽  
Osteoblast Progenitors

Runx2 is essential for osteoblast differentiation and chondrocyte maturation. During osteoblast differentiation, Runx2 is weakly expressed in uncommitted mesenchymal cells, and its expression is upregulated in preosteoblasts, reaches the maximal level in immature osteoblasts, and is down-regulated in mature osteoblasts. Runx2 enhances the proliferation of osteoblast progenitors by directly regulating Fgfr2 and Fgfr3. Runx2 enhances the proliferation of suture mesenchymal cells and induces their commitment into osteoblast lineage cells through the direct regulation of hedgehog (Ihh, Gli1, and Ptch1), Fgf (Fgfr2 and Fgfr3), Wnt (Tcf7, Wnt10b, and Wnt1), and Pthlh (Pthr1) signaling pathway genes, and Dlx5. Runx2 heterozygous mutation causes open fontanelle and sutures because more than half of the Runx2 gene dosage is required for the induction of these genes in suture mesenchymal cells. Runx2 regulates the proliferation of osteoblast progenitors and their differentiation into osteoblasts via reciprocal regulation with hedgehog, Fgf, Wnt, and Pthlh signaling molecules, and transcription factors, including Dlx5 and Sp7. Runx2 induces the expression of major bone matrix protein genes, including Col1a1, Spp1, Ibsp, Bglap2, and Fn1, in vitro. However, the functions of Runx2 in differentiated osteoblasts in the expression of these genes in vivo require further investigation.

Oxysterols enhance osteoblast differentiation in vitro and bone healing in vivo

2007 ◽  
Vol 25 (11) ◽  
pp. 1488-1497 ◽  
Author(s):  
Tara L. Aghaloo ◽  
Christopher M. Amantea ◽  
Catherine M. Cowan ◽  
Jennifer A. Richardson ◽  
Ben M. Wu ◽  
...  
Keyword(s):  
Bone Healing ◽  
Osteoblast Differentiation

Preparation and In Vitro Characterization of Polycaprolactone and Demineralized Bone Matrix Scaffolds

2012 ◽  
Vol 1417 ◽  
Author(s):  
Titilayo Moloye ◽  
Christopher Batich
Keyword(s):  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Apatite Formation ◽  
Alizarin Red ◽  
Salt Leaching ◽  
Synthetic Materials ◽  
Calcium And Phosphorus ◽  
Demineralized Bone

ABSTRACTCylindrical porous polycaprolactone (PCL) scaffolds containing 25, 35, and 50 wt% demineralized bone matrix (DBM) were fabricated using a salt-leaching method for application in bone engineering. In the present work, PCL-DBM scaffolds were monitored for calcium and phosphorus deposition in both deionized (DI) water and simulated body fluid (SBF) for time periods of 5, 10, 15, and 20 days at 37°C under constant rotation. An in vitro assessment of the bioactivity of synthetic materials using SBF under physiological conditions can be used as a barometer of scaffold behavior in vivo. DBM, an osteoinductive material, was used to gauge if there was a correlation between the concentration of DBM within a scaffold and the apatite formation on its surface. Biochemical assays, alizarin red S staining, and scanning electron microscopy (SEM) with elemental analysis of calcium and phosphorus were consistent in that they confirmed that PCL scaffolds containing 35 wt% DBM in SBF at 14 days post-immersion showed signs of early apatite formation.

scholarly journals Lithium Chloride Exerts Differential Effects on Dentinogenesis and Osteogenesis in Primary Pulp Cultures

2021 ◽  
Vol 2 ◽  
Author(s):  
Anushree Vijaykumar ◽  
Mina Mina
Keyword(s):  
Dental Pulp ◽  
Osteoblast Differentiation ◽  
Prolonged Treatment ◽  
Odontoblast Differentiation ◽  
Positive Effects ◽  
Reparative Dentin ◽  
Dentin Formation ◽  
Reparative Dentin Formation

Wnt/β-catenin signaling is known to play essential roles in odontoblast differentiation and reparative dentin formation. Various Wnt activators including LiCl have been increasingly studied for their effectiveness to induce repair of the dentin-pulp complex. LiCl is a simple salt thought to activate Wnt/β-catenin signaling by inhibiting GSK3β. Previous in vitro and in vivo studies showed that LiCl increased odontoblast differentiation and enhanced reparative dentin formation. However, the underlying molecular and cellular mechanisms by which LiCl regulates odontoblast and osteoblast differentiation during reparative dentinogenesis are not well-understood. Our in vitro studies show that exposure of early dental pulp progenitors to LiCl increased the survival and the pool of αSMA+ progenitors, leading to enhanced odontoblast and osteoblast differentiation. The positive effects of LiCl in the differentiation of osteoblasts and odontoblasts from αSMA+ progenitors are mediated by Wnt/β-catenin signaling. Our results also showed that continuous and late exposure of dental pulp cells to LiCl increased the expression of odontoblast markers through Wnt/β-catenin signaling, and the number of odontoblasts expressing DMP1-Cherry and DSPP-Cerulean transgenes. However, unlike the early treatment, both continuous and late treatments decreased the expression of Bsp and the expression of BSP-GFPtpz transgene. These observations suggest that prolonged treatment with LiCl in more mature cells of the dental pulp has an inhibitory effect on osteoblast differentiation. The inhibitory effects of LiCl on osteogenesis and Bsp were not mediated through Wnt/β-catenin signaling. These observations suggest that the effects of LiCl, and GSK3β antagonists on reparative dentinogenesis involve multiple pathways and are not specific to Wnt/β-catenin signaling.

scholarly journals Osteoclast-Derived Extracellular miR-106a-5p Promotes Osteogenic Differentiation and Facilitates Bone Defect Healing

2021 ◽  
Author(s):  
Yutong Wu ◽  
Hongbo Ai ◽  
Yuchi Zou ◽  
Jianzhong Xu
Keyword(s):  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Signal Molecules ◽  
Calvarial Defect ◽  
Communication Mode ◽  
Defect Healing ◽  
Bone Defect Healing ◽  
Intercellular Communications

Abstract Small extracellular vesicles (sEVs) are considered to play critical roles in intercellular communications during normal and pathological processes since they are enriched with miRNAs and other signal molecules. In bone remodeling, osteoclasts generate large amounts of sEVs. However, there is very little research about whether and how osteoclast-derived sEVs (OC-sEVs) affect surrounding cells. In our study, microarray analysis identified miR-106a-5p highly enriched in OC-sEV. Further experiments confirmed that OC-sEVs inhibited Fam134a through miR-106a-5p and significantly promoted bone mesenchymal stem cell (BMSC) osteogenic mineralization in vitro. Next, we prepared sEV-modified demineralized bone matrix (DBM) as a repair scaffold, and used a calvarial defect mouse model to evaluate the pro-osteogenic activities of the scaffold. In vivo result indicated DBM modified with miR-106a-5p-sEVs showed an enhanced capacity of bone regeneration. This important finding further emphasizes that sEV-mediated miR-106a-5p transfer play critical roles in osteogenesis and indicate a novel communication mode between osteoclasts and BMSCs.

scholarly journals LOSS OF PROTEINPOLYSACCHARIDES AT SITES WHERE BONE MINERALIZATION IS INITIATED

1972 ◽  
Vol 20 (4) ◽  
pp. 279-292 ◽  
Author(s):  
D. BAYLINK ◽  
J. WERGEDAL ◽  
E. THOMPSON
Keyword(s):  
Calcium Concentration ◽  
Bone Mineralization ◽  
Bone Matrix ◽  
Indirect Evidence ◽  
Experimental Conditions ◽  
Acid Polysaccharide ◽  
Major Acid ◽  
Tibial Cortex

In both ground sections and demineralized frozen sections of the rat tibial cortex, osteoid but not mature bone matrix stained for proteinpolysaccharides with the Alcian Blue and toluidine blue techniques. The loss of proteinpolysaccharide staining occurred precisely at the mineralizing front, which was identified by in vivo lead or procion markers, not only in normal animals but also in animals in which osteoid width was either increasing or decreasing. In vitro, both proteases and saccharidases abolished proteinpolysaccharide staining of osteoid. Critical electrolyte concentration and other procedures indicated that the major acid polysaccharide component in osteoid is chondroitin sulfate. Consistent with these findings, electron microprobe analyses revealed that sulfur concentration was high in osteoid but dropped abruptly as calcium concentration increased at the mineralizing front. The precise synchronization between loss of proteinpolysaccharides and onset of mineralization under various experimental conditions provides strong indirect evidence that the loss of these macromolecules is somehow involved in initiation of mineralization in bone.

Osseoinduction Evaluation of Hydroxyapatite and Zinc Containing Hydroxyapatite Granules in Rabbits

2011 ◽  
Vol 493-494 ◽  
pp. 252-257 ◽  
Author(s):  
L. Nascimento ◽  
M. Medeiros ◽  
J. Calasans-Maia ◽  
A. Alves ◽  
Antonella M. Rossi ◽  
...  
Keyword(s):  
Histological Analysis ◽  
Bone Matrix ◽  
Fibrous Tissue ◽  
Particle Diameter ◽  
Inflammatory Cells ◽  
Giant Cells ◽  
Multinucleated Giant Cells ◽  
Ethics Commission

This study investigated the osteoinductive potential of granules of stoichiometric hydroxyapatite (HA) and 0.5% zinc containing hydroxyapatite (ZnHA) in intramuscular (IM) site of rabbit’s abdomen. The biomaterials were both used in granular form, with 75% porosity and particle diameter between 450 and 500μm, sintered at 1100°C. Both materials performed adequately on a multiparametric in vitro cytocompatibility assay, indicating their suitability for in vivo testing. After approval by the Ethics Commission on Teaching and Research in Animals, fifteen rabbits were submitted to general anesthesia, incision and tissue dilatation, and a small site was created for HA (right incision) and ZnHA (left incision) intramuscular implantation. The animals were killed after 2, 4 and 12 weeks for biomaterials and surrounding tissues removal. Histological analysis after 2 weeks revealed the presence of granulation tissue surrounding biomaterials with multinucleated giant cells and no newly formed bone for both materials. After 4 weeks there was fibrous tissue involving the material and few inflammatory cells. Following 12 weeks it was observed the presence of connective tissue surrounding the biomaterial, cellularized enough for the two experimental groups, but it was not observed the presence of bone matrix associated with the biomaterials. We conclude that both biomaterials are cytocompatible and did not present the property of osseoinduction after 12 weeks of implantation.

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